The present invention relates to stereomicroscopes, and more particularly to stereomicroscopes used to detect differences between substantially identical photographs, either aerial photographs or photographic masks used by the semi-conductor industry.
U.S. Pat. No. 3,879,107, issued to Chaban Apr. 22, 1975, discloses a stereomicroscope of the type used to compare aerial photographs. The disclosed stereomicroscope has two optical systems with each system having a rhomboid arm used to position the respective objective over the pertinent portion of a respective aerial photograph. Each rhomboid arm contains an independent zoom system to produce an intermediate image which is then relayed through the respective optical system to a respective image rotator. A beamsplitter or mirror selectively placed at the intersection of the optical axes of the optical systems permits either mono or stereo presentation of the respective image from each rhomboid arm.
Stereomicroscopes of the type disclosed in the Chaban patent are conventionally used to compare two aerial photographs or a mask with a master, in connection with the preparation of semi-conductor wafers. The comparison is conducted by placing one of the photographs or wafer or mask under one rhomboid arm and the other photograph or wafer or mask under the other rhomboid arm. The rhomboid arms are then moved until substantially the same object is located in each photograph. The fields of view are then angularly adjusted by the operator, using the image rotators to rotate either or both images until they both have an identical orientation. The operator then adjusts either or both zoom systems until the sizes of the two images are identical. It may then be necessary to slightly reposition the rhomboid arms or one of the photographs or wafers or masks until the two fields of view are identical, which may also require a further repetition of the above described adjustment steps. Although not disclosed in the Chaban patent, it is conventional in such stereomicroscopes to permit superimposition of the images. That is, the image from one rhomboid arm is presented to both eyepieces and the image from the other rhomboid arm is presented to both eyepieces. Many operators prefer to use this superimposed mode to conveniently obtain proper orientation, image size and identical fields.
It is an object of the present invention to provide means for recording, as digital images, visual images being observed through a stereoscope.
It is another object of the present invention to provide means for magnifying, rotating and/or warping visual images as they are digitally recorded.
It is still another object of the present invention to permit means for introducing digitally recorded images as visual images into a stereoscope.
It is still another object of the present invention to provide means for magnifying, rotating and/or warping digitally recorded images as they are introduced as visual images into a stereoscope.